pin cool.io to 1.9.0

Author: zanejohnson-azure

kubernetes/linux/setup.sh

@@ -81,7 +81,7 @@ fluentd_version="1.16.3"
 
 # Pre-install cool.io to avoid ARM64 build issues (segfault during native extension compilation)
 if [ "$ARCH" == "arm64" ]; then
-    gem install cool.io -v "1.8.0" --no-document
+    gem install cool.io -v "1.9.0" --no-document
 fi
 
 gem install fluentd -v $fluentd_version --no-document